Synthesis of polymeric calix[4]arene dinitrile and diamino-derivatives: Exploration of their extraction properties towards dichromate anion

The article describes the syntheses and extraction properties of new alkylnitrile and alkylamino substituted calix[4]arene based copolymers. These compounds have been synthesized via nucleophilic substitution reactions involving 5,11,17,23-tetra-tert-butyl-25,27-bis(cyanomethoxy)-26,28-dihydroxycalix[4]arene (3), or 25,27-bis(cyanomethoxy)26,28-dihydroxycalix[4]arene (4) with 1,5-dibromopentane and bisphenol-A, followed by their reduction with sodium borohydride in the presence Of CoCl2.6H(2)O. In addition an oligomer containing pendant calix[4]arene units with nitrile functionalities on its lower rim has been synthesized via nucleophilic reaction involving 5,11,17,23-tetra-tert-butyl-25,27-bis(cyanomethoxy)-26,28-dihydroxycalix[4]arene 3 with p-dibromoxylene. The extraction properties of polymers 5-9 toward the HCr2O7- anion are also reported. Due to the higher oxidative stability of nitrile groups, polymers 5-7 have been developed as good extractants for transferring the HCr2O7- anion from an aqueous into a dichloromethane phase.